Pick resistant lock having laterally movable wafers

ABSTRACT

A pick-resistant lock construction in which the rotating plug disposed within a relatively fixed cylinder comprises a plurality of generally planar plug elements each supporting a resiliently urged locking wafer which in relatively unstressed condition engages a corresponding recess in the fixed cylinder. The plug elements define a recess accommodating a wafer, the recess including a laterally extending portion. The wafer includes a corresponding laterally oriented surface which will clear said laterally extending portion of said recess with normal operation of the lock. The wafer executes a small degree of rotational motion relative to a plug element when an attempt is made to rotate the plug element during a picking operation, so that subsequent rectilinear motion of the wafer relative to the plug element imparted by a picking instrument will cause engagement of said laterally oriented surface with said laterally extending portion of said recess to inhibit further longitudinal motion to a degree sufficient to prevent disengagement of the wafer from the cylinder.

United States Patent [191 Mercurio Dec. 17, 1974 1 PICK RESISTANT LOCK HAVING LATERALLY MOVABLE WAFERS [76] Inventor: Leonard Mercurio, 34 Beaumont Dr., Plainview, NY. 11803 22 Filed: Oct. 29, 1973 211 Appl. No.: 410,428

[52] US. Cl 70/364 R, 70/377, 70/419 [51] Int. Cl E05b 15/14, E05b 29/02 [58] Field of Search 70/364 R, 377, 419, 421

[56] References Cited UNlTED STATES PATENTS 2/1878 Coleman 70/364 R 8/1891 Stein 70/377 X 1,406,573 2/1922 Manteufel...

1,406,574 2/1922 Manteufel 70/364 R 1,600,661 9/1926 Winning 70/364 R 1,964,963 7/1934 Shinn l 70/364 R 2,330,929 10/1943 Shinn 70/364 RX Navarro 70/377 X Primary Examiner-Robert L. Wolfe Attorney, Agent, or Firm Char1es E. Temko [57] ABSTRACT A pick-resistant lock construction in which the rotating plug disposed within a relatively fixed cylinder comprises a plurality of generally planar plug elements each supporting a resiliently urged locking wafer which in relatively unstressed condition engages a corresponding recess in the fixed cylinder. The plug elements define a recess accommodating a wafer, the recess including a laterally extending portion. The wafer includes a corresponding laterally oriented surface which will clear said laterally extending portion of said recess with normal operation of the lock. The wafer executes a small degree of rotational motion relative to. a plug element when an attempt is made to' rotate the plug element during a picking operation, so that subsequent rectilinear motion of the wafer relative to the plug element imparted by a picking instrument will cause engagement of said laterally oriented surface with said laterally extending portion of said recess to inhibit further longitudinal motionlto a degree sufficient to prevent disengagement of the wafer from the cylinder.

1 Claim, 7 Drawing Figures PATENTEL LIKE I 7 I974 FIG.2

FIGJ

PICK RESISTANT LOCK.I-IAVING LATERALLY MOVABLE WAFERS BACKGROUND OF THE INVENTION opening in the plug, the key aligns the resiliently urged members so that a parting line is brought into coincidence with the arcuate peripheral surface of the plug element, and when all of such resiliently urged members are aligned, a rotational motion imparted to the key permits the plug to turn. With normal commercial tolerances, it is impossible to precisely place all of the resiliently urged members on a straight line, and the usual manner of picking such a lock is to insert a picking tool into the opening in the lock, and exert a torque on the plug element so that with successive in and out motions, the resiliently urged member first placed in compression is aligned for clearance, at which point the plug rotates a very small degree to bring the next resiliently urged member into a similar compressed condition. The operation is repeated until all of the resiliently urged membersihave beenfovercome, at which point the plug may' be' rotated. Thus, each locking member is individually overcome by. random movement of the same radially of the plug until a parting line is aligned with theabutting surfaces of the cylinder and plug.

Many attempts-have been made to provide cylinder locks which are resistant to such picking operation. In some cases, the resiliently urged members are so constructed that the overcoming of one of the same automatically locks the'remaining members against further movement. In other constructions, additional recesses are provided-in the fixed cylinder so that after a resiliently urged member has been overcome it re-engages,

in the absence of clearance of the remaining resiliently urged members, again with the cylinder to prevent further rotation. In some constructions, an attempt to pick the lock results in movement to aposition where it is totally disabled, and cannot subsequently be opened even by authorized persons, necessitating the drilling out of the lock and the reinstallation of a new one.

BRIEF DESCRIPTION OF THE PRESENT INVENTION Briefly stated, the invention contemplates the provision of an improved lock of the class described, in

. which the resiliently urged locking members Y which project fromthe plug to engage the cylinder are capafirst resiliently urged member to be placed in shear cannot be cleared from the cylinder, and the picking effec-' tively prevented.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings, to which reference will be made in the specification, similar reference characters have been employed to designate corresponding parts throughout the several views.

FIG. 1 is a view in elevation of a single plug element comprising a part of the disclosed embodiment.

FIG. 2 is an elevational view of a single wafer and as v sociated coil spring.

FIG. 3 is a schematic transverse sectional view of an assembled lock embodying the invention.

FIG. 4 is a similar sectional-view showing certain of the component parts in altered relative position.

DETAILED DESCRIPTION OF TI-IEDISCLOSE EMBODIMENT 1 In accordance with the invention, the device, generally indicated by reference character 10, comprises broadly; an outer relatively fixed cylinder 1 l, and a plurality of interconnected plugelement's12, each having a locking wafer 13 slidably mounted thereon. A key 14 is selectively engageable with the plug elements in normal manner. v

Referring to FIG. 7, the cylinder 11 is generally conventional, being bounded byan outer surface 15, a forward rim 1 6, and a forward surface 17 defining an axially disposed opening 18. Positioned rearwardly of the opening '18 is a fixed cover plate 19 having a keyhole opening 20 leading to a-central bore 21. Extending radially of the bore are longitudinal grooves 22 (FIGS. 3 and 4) which provide a locking function with the wafers 13 in well-known manner.

Referring to FIGS. 1 to .4, inclusive, theplug elements 13 are generally similar, each being of disc-like.

configuration and being bounded by a planar rear surface 24, an arcuate peripheral surface 25 and a forward surface 26. A pair of longitudinal bores 27 mate with interconnecting pins 28 to gang or integrate each of the elements 12 into a single unit.

Extending from the forward surface26 is a first generallyrectangular recess 29 which accommodates a wafer 13, bordered by an elongated recess 30 accommodating a coil spring 31. A right hand (as seen in FIG. 1) wall 32 is generally rectilinear, and includes an outwardly diverging portion 33 leading to a recess 34 bounded by a locking shoulder or projection 35.

The wafers 13 are all similar, and are bounded by a pair of planar surfaces 37. A main body 38 is of rectanto the plug and to induce motion of the resiliently urged members by a picking tool. Instead of moving through a normal path, the canting causes the resiliently urged members to engage a shoulder on the plug which prevents further radially inward motion prior to -disengagement'of the resiliently urged member with the cylinder. Thus, during an attempted picking-operation, even the gular configuration, and supports a locking projection 39 at one end, and a second locking projection 40 at v I another. A laterally extending projection 41 engages the end of the spring 31 for the impartation of motion therethrough. A rectangular opening 42 p'rovides-ingress for the key 13, and a lower transverse edge 43 is disposed at an angle other than a right angle with respect to the adjacent edges to-serve as a camming surface with respect to a picking tool as will more fully ap- FIG. 5 is a front elevational view of a fully assembled 3 pear. A right hand edge 44 is provided with first and second projections 45 and 46 which form bearing surfaces guiding the wafer 13 along the wall 32. These projections define a discontinuous contact,and the formation of a recessed portion 47 which permits canting of thewafer relative to the plug.

The key member 14 is of a conventional type, including a manually engageable head 48, a narrow shoulder portion 49 accommodating the opening in the plate 19 to permit rotation, and an elongated shank 50 having laterally extending projections 51 engaging selectively the edge 43 of each wafer.

During normal operation, the insertion of the key will align the wafers 13 so that the locking projections 39 and 40 will be placed in the recess 29 to permit the plug elements 12 to be rotated. Withdrawal of the key permits the wafers, under the action of the coil springs 31 to return to locking position and inhibit movement of the plug elements relative to the cylinder.

When an attempt is made to pick the lock, and the plug elements 12 are rotated to place the wafers 13 in shear prior to moving the wafers radially using a pickchannels 51 and 50, they will enter these channels and again lock the plug elements against further rotation. In this position, only a small circular central portion of the opening 40 will be available to the unauthorized person, and further picking operations substantially impossible.

I wish it to be understood that 1 do not consider the invention limited to the precise details of struction shown and set forth in this specification, for obvious modifications will occur to those skilled in the art to which the invention pertains.

I claim: I

1. in a pick-resistant tumbler lock of a type including a relatively fixed cylinder defining a cylindrical bore, at least one plug elementarranged for relative rotation within said bore, said plug element having a resiliently urged wafer slidably mounted thereon for selective proing tool (not shown), the shear is resisted by contact of the second projection 46 against the wall 32. However,

as the wafer moves inwardly of the plug element under' the influence of the picking tool, as soon as the projection 46 reaches the portion '33 of the wall 32, the wafer becomes canted, so that the laterally positioned surface 52 enters the recess 34 and engages the projection or shoulder 35. At this point, further inward motion is not possible, and the wafer must be released from the picking tool to permit any subsequent movement whatsoever.

It will be apparent that this action will occur with whatever wafer is. first placed in shear with the above described rotational motion, this operation being known in the art as torquing. Upon release, the wafer remains to its original undisturbed condition, without damage, and the lock may be subsequently operated by theinsertion of the proper key.

The device also contemplates an additional safety factor in the provision of additional channels 50 and 51 (FIGS. 3 and 4) which are parallel to the channels 22 in the element 11. Should, by the use of a picking tool the unauthorized person be able to getall of the wafers 13 to the position shown in FIG. 3, and commence to rotate the integrated elements 12 through a small increment, the absence of a key willpermit the wafers 13 to return under the influence of the springs. When the plug elements have reached a position in which the projections 39 and 40 are aligned, respectively with the jection radially outwardly-to engage a corresponding groove in said fixed cylinder, the improvement comprising: said plug element having a radially extending recess therein, said wafer being'disposed within said recess, said recess having a generally rectilinear wall at one side thereof, said wafer having corresponding edge surfaces slidably contacting saidwall whereby said wafer may execute rectilinear motion relative thereto, said generally rectilinear side wall having a recess therein defining a shoulder, said water having a laterally extending surface thereon selectively engageable with said shoulder accompanying a small degree of pivotal motion of said wafer relative to said recess; said wafer defining a generally rectangular opening therein for entrance of a key shank, at least one of the'edges defining said opening being disposed in nonrectangular relation to form a camming surface cooperating with a picking tool to urge said wafer into engagement with said shoulder; whereby upon the occurrence of an attempt to pick said lock by exerting a torque upon said plug element relative to said cylinder element, and urging said wafer to a point where said wafer disengages said relatively fixed cylinder, said wafer will be urged to cantered relation relative to theaxis of said plug element, and predisposed to enter said recess upon inward movement to engage said'shoulder prior to disengagement of said wafer from said fixed cylinder, said cantered relation occurring in the absence of exerting said torque upon the insertion of a picking tool into said plug element, and the contact of said picking tool with said one of said edges defining said opening. 

1. In a pick-resistant tumbler lock of a type including a relatively fixed cylinder defining a cylindrical bore, at least one plug element arranged for relative rotation within said bore, said plug element having a resiliently urged wafer slidably mounted thereon for selective projection radially outwardly to engage a corresponding groove in said fixed cylinder, the improvement comprising: said plug element having a radially extending recess therein, said wafer being disposed within said recess, said recess having a generally rectilinear wall at one side thereof, said wafer having corresponding edge surfaces slidably contacting saId wall whereby said wafer may execute rectilinear motion relative thereto, said generally rectilinear side wall having a recess therein defining a shoulder, said wafer having a laterally extending surface thereon selectively engageable with said shoulder accompanying a small degree of pivotal motion of said wafer relative to said recess; said wafer defining a generally rectangular opening therein for entrance of a key shank, at least one of the edges defining said opening being disposed in non-rectangular relation to form a camming surface cooperating with a picking tool to urge said wafer into engagement with said shoulder; whereby upon the occurrence of an attempt to pick said lock by exerting a torque upon said plug element relative to said cylinder element, and urging said wafer to a point where said wafer disengages said relatively fixed cylinder, said wafer will be urged to cantered relation relative to the axis of said plug element, and predisposed to enter said recess upon inward movement to engage said shoulder prior to disengagement of said wafer from said fixed cylinder, said cantered relation occurring in the absence of exerting said torque upon the insertion of a picking tool into said plug element, and the contact of said picking tool with said one of said edges defining said opening. 